Definitely my email list...unfortunately, we do not own social media and at any point it could implode into nothingness, or we could be kicked out or locked out without notice and lose all access to those we are influencing (this has happened to big name business owners, so not a scare tactic).  I DO own my email list and I can continue to communicate with my audience on there, that is why I am ALWAYS pointing them in that direction.  As a social media manager and strategist, I LOVE social media, but I also have to be aware of what 'could' happen in the future and plan for that accordingly!